Natural gas is sometimes used as a fuel source for trains. Natural gas can be an attractive alternative to diesel fuel because it can be less expensive to produce and procure, and produces less carbon dioxide when burned. Natural gas is readily available as a fossil fuel, and can also be produced from waste at man-made facilities. However, in many areas of the world, including in the United States, the natural gas infrastructure (e.g. natural gas facilities, storage sites, pipelines, etc.) is not as developed as the infrastructure for diesel fuel. Also, natural gas can be challenging to store and/or transport long distances, reducing the benefit of using natural gas as a fuel source.